A man who helps poor, immigrant and minority families in San Francisco take steps toward financial security was one of 23 people honored Thursday with "genius grants" from the MacArthur Foundation.

MacArthur Fellows are chosen for their creativity, significant achievements and potential. They get $625,000 over five years in a bid to give them the financial freedom to pursue their projects and, the foundation hopes, make the world a better place.

Financial innovator Jose Quinonez said about 7 percent of Americans do not have bank accounts and do not show up on the credit rating system. Without a credit history, it is hard for them to borrow money, rent an apartment, get some jobs or start a business.

Quinonez, an immigrant, drew on traditional lending practices in Latin America, Asia and Africa, organizing "lending circles" where groups of neighbors and others pool their money to make small loans. Each member has to attend a financial education class and convince fellow members that he is likely to repay the loan. Quinonez said more than 99 percent of the loans get repaid.

Quinonez and the organization he started, Mission Asset Fund, have formalized the lending circle practice, tracking borrowing and repayment activity. Results are reported to major credit bureaus, giving clients a proven repayment history. Positive credit reports make conventional banks willing to make loans to these clients in the future.

Borrowing is a crucial step for small entrepreneurs who want to start a cafe or other small business, which is a major step out of poverty.

A number of other organizations are using Mission Asset Fund as a blueprint to set up similar programs in other cities.

Other members of this year's class of MacArthur Fellows included a human rights lawyer, a linguist, a microbiologist, a sculptor, computer scientists and a poet.